1. Field of the Invention
This invention lies in the field of producing oil wells. More particularly, it concerns wells of a pumping status of which the greatest majority are wells producing oil and water. In the minority of the cases, those that produce very little or no water have paraffin problems. The chemicals that can be used in this patent can correct the paraffin problem.
The great majority of oil wells carry a certain percentage of water with the oil, in which are minerals and/or chemicals that precipitate from solution as the water flows into the well, either through perforations, or in open formation completions. This forms a scale of gypsum, barium, and/or other minerals that clog porosity, restricting the flow of oil into the borehole. These precipitates also affect pumping equipment by their coatings, causing standing valves and pump barrels to pit, wear, and lose efficiency.
This also requires expensive well servicing operations to pull all pumping equipment out of the well and to inject well treating chemicals into the well to remove these deposits. There are many commercial chemicals that can dissolve this material, but the big problem is to position these chemicals directly on the bottom of the hole, at the producing formation, so that the formation wall and pores can be cleaned.
The crux of the problem is to provide the treating on a continuous basis, at a rate proportional to the influx of water and contamination it carries, and to position the chemicals at the bottom of the hole to treat the water as it flows in, and also to treat the interior of the pump and tubing as the oil and water are pumped out.
2. Description of the Prior Art
In the prior art there have been many types of apparatus and procedures designed to place chemicals of of selected composition in position on the well bottom. None of these devices have eliminated the need for expensive work-overs. The fact is that gypsum and other contaminating precipitates remain a constant problem in oil production.
Some of these processes provide for dripping or pouring a liquid chemical solution, at selected intervals, down the annulus of the well. It is doubtful whether these solutions ever do any more than coat the casing and tubing. In any event they can, at best, only reach the perforated nipple at the pump inlet, and be pumped back to surface. Certainly they cannot reach a level below the fluid level standing in the casing, usually far above the intended treating zone, the producing zone.
This invention describes an apparatus for providing a supply of chemical on bottom, and metering it out as a function of the rate of flow of fluid into the well.